In a Long Term Evolution (English: Long Term Evolution, LTE for short) or Long Term Evolution-Advanced (English: Long term evolution-advanced, LTE-A for short) system, there are a plurality of transmission modes (English: Transmission mode, TM for short), for example, TM1 to TM10. A base station may use radio resource control (Radio Resource Control, RRC for short) signaling to instruct UE to transmit data in a corresponding TM. Each of the plurality of TMs includes two transmission schemes. The base station may deliver transmission scheme indication information to the user equipment (English: User equipment, UE for short) based on channel quality. The transmission scheme indication information may indicate one transmission scheme in the TM currently used by the UE. The UE may use the corresponding transmission scheme based on the transmission scheme indication information, to transmit data. The channel quality may be represented by channel state information (English: Channel state information, CSI for short).
In the related art, each of TM3 to TM10 includes two transmission schemes: a non-transmit diversity multiple-input and multiple-output (English: Multiple-input and multiple-output, MIMO for short) transmission scheme and a non-beamforming transmit diversity (English: Non-beamforming transmit diversity, NBTD for short) transmission scheme. For example, TM5 includes a multi-user MIMO transmission scheme and a transmit diversity transmission scheme. In the non-transmit diversity MIMO transmission scheme, different UEs can perform spatial multiplexing of a time-frequency resource, or same UE can simultaneously transmit a plurality of spatial flows (in other words, symbol layers or spatial layers), to improve spectral efficiency. The non-transmit diversity MIMO transmission scheme is applicable to a scenario with relatively good channel quality. The NBTD transmission scheme can effectively resist channel fading, increase a signal-to-noise ratio at a receive end, and ensure reliability of UE data transmission, and is applicable to a scenario with relatively poor channel quality. UE may report CSI to a base station. Based on the CSI reported by the UE, the base station uses downlink control information (English: Downlink control information, DCI for short) to instruct the UE to transmit data by using a corresponding transmission scheme.
In a process of implementing this application, the inventor finds that the related art has at least the following problem:
A TM in the related art includes a non-transmit diversity MIMO transmission scheme and an NBTD transmission scheme, and UE can use only the non-transmit diversity MIMO transmission scheme or the NBTD transmission scheme according to indication of a base station, to transmit data, resulting in relatively low flexibility in UE data transmission.